on i7@2.6GHz it looks like:

thread runtime:

    name              time/op
    pyx_select_nogil  2.70µs ±13%
    pyx_go_nogil      15.9µs ± 1%
    pyx_chan_nogil    2.79µs ± 2%
    go                17.6µs ± 0%
    chan              3.05µs ± 4%
    select            3.62µs ± 4%

gevent runtime (gevent-1.4.0):

    name              time/op
    pyx_select_nogil  9.39µs ± 1%
    pyx_go_nogil      15.1µs ± 2%
    pyx_chan_nogil    7.10µs ± 1%
    go                16.6µs ± 1%
    chan              7.47µs ± 1%
    select            10.7µs ± 0%